I think this will be huge. Just check it out: http://web.mit.edu/newsoffice/2008/oxygen-0731.html And no, that's not my friend's site or anyone else's I know personally, although, being a physicist, my friend happens to know one of these fellows.
Interesting stuff, but solar panels will need to be efficient enough to produce not only what your house consumes, but also enough for electrolysis. That can be a tall order in the summer, when you've got two a/c systems and a fridge running all day long.